Pluto's newly discovered moons now have names.
Known previously as
P4 and P5, the
International Astronomical Union has now
given the fourth and fifth discovered moons of
Pluto the names
The small moons were discovered in 2011 and 2012 by the
Hubble Space Telescope in preparation for the close passing of the
New Horizons spacecraft by Pluto in 2015.
is named for the
many headed dog in
Greek mythology that guards the entrance to the underworld, while
Styx is named for the
goddess who overlooks the
mythological river that runs between the Earth and the underworld.
Both monikers are related to the name of Pluto, who rules the
mythical nether region.
Because their reflectively is unknown, the size of each moon is quite uncertain -- but each is crudely estimated to be about 20 kilometers in diameter.
The robotic New Horizons spacecraft is on schedule to pass by Pluto in 2015 and provide the first clear images of the
dwarf planet and its companions.